Using JOA
with EPIC (at PMEL)
Introduction
Using JOA with EPIC involves using either the epicselect program
in Solaris or the EPIC Web Browser (http://www.epic.noaa.gov/)
in the Windows (you can also use EWB in Solaris if you prefer)
to create and download a pointer file that can be opened in
JOA. Pointer files can be opened directly by JOA meaning that
the actual data files will be opened into a JOA data window
or the pointer file can be opened in the NdEdit module for further
refinement and selection of profiles of interest. Refer to the
tutorial below for an example of this process.
Memory Considerations
If the number of entries in the pointer file is relatively
small or you are working exclusively with bottle data, you can
open the pointer file directly in JOA to open the associated
profiles. JOA has been successfully tested with pointer files
containing over 500 bottle profile entries. If you are working
with full-depth, full-resolution CTD profiles, you will be able
to open far fewer profiles before you hit memory limitations
on your machine. JOA has many options for decimating CTD data
which may allow you to open a much larger number of profiles.
Decimation settings are found using the Preferences command
in the Edit menu.
Using EPIC Pointer File on Windows PCs
Before using the Epic Web Browser, you must make the actual
EPIC data files available to your PC via NFS. You do this by
mounting a specific network drive as the "Q:" drive on your
PC.
Step #1: Right click on the My Computer icon on the
desktop and select Map Network Drive.
Step #2: In the Map Network Drive dialog, select the
"Q:" drive from the Drive popup menu.
Step #3: In the scrolling list select EPIC NFS in the
Pesto node:
Step #1: Open the EPIC Web Browser web site at http://www.epic.noaa.gov/.
You will then see the main EPIC window. Click on either the
public access or PMEL local links to start browsing
the database. You will see the main page for the EPIC Web Browser:
Step #2: Since JOA is designed for profile data, click the
Profile data selection link. You will then see the Dataset
Selection page.
Step #3: Select any combination of CTD, Bottle or XBT datasets.
The web page will summarize the number of profiles, list the
date range, and show the geographic extents of the selected
datasets on the world map. Click the Next button to go
to the Data Selection Search Criteria page:
Step #4: Refine your selection by entering date, depth, or
location limits or searching for string attributes in the data
files. You can define location range by dragging a selection
rectangle on the map showing the station locations for the selected
datasets. Click the Next or Search button to go
to the Data Display and Access page.
Step #5: From the Pointer File Options popup menu (near
the bottom of this page), select Download Pointer File.
Click the GO button to go to the Download Pointer
File page:
Step #6: Depending upon your platform (Solaris or Windows)
right click on either the Unix Complete Format Pointer File
or PC Complete Format Pointer File links. You will be
prompted to save the pointer file to location on your local
machine:
Step #7: Launch JOA 3.1. Click the small triangle next
to Show NdEdit to display the NdEdit data browser. Select
Open pointer collection from the File menu and
open the pointer file you downloaded in the previous step:
You will see the individual profiles displayed as small x symbols
in the NdEdit browsing panels:
Step #8: Use NdEdit's data selection features and filters to
further refine your final data selection. Note: a separate NdEdit
tutorial is available at http://www.pmel.noaa.gov/epic/software/JavaNdedit.htm.
After narrowing the time domain and zooming into Kodiak Island,
the NdEdit display now looks like:
This figure also illustrates the use of the Section tool to
select a series of profiles in Shelikof Strait. The following
figures shows the selected profiles as highlighted symbols:
Step #9: Open the selected files in JOA. Choose the Open
selected files command in the File menu. You will
be see the Configure Sort Options dialog:
Step #10: You can optionally sort the pointer file entries
by location and depth . In addition you can specify the sorting
order. After you have specified any pointer file sorting, click
the OK button to open the selected profiles on JOA:
